Although the main intrinsic parameters in Silicon Carbide material have not been exhaustively studied, several experimental and theoretical studies have been performed in recent years in order to better describe the current transport in ohmic and rectifying contact on SiC.
It has been known that in Schottky diodes the metal semiconductor interface (MST) between the Schottky barrier metal and the semiconductor plays a crucial role in the electrical performance of electronic devices. Many factors can worsen the performance of the MSI in a Schottky diode. For example, the quality of the semiconductor surface prior to the deposition of the Schottky barrier metal can cause the device to exhibit characteristics that are different from the ideal characteristics.
Current-voltage (I-V) and capacitance-voltage (C-V) characterizations are useful methods for determining the Schottky barrier height from which the MSI uniformity can be obtained. It has been known that the barrier height determined from C-V measurements often exceeds the value extracted from forward I-V measurements. The discrepancy is also seen to be greater for Schottky contacts with high ideality factor, i.e. poor Schottky MSI quality. Sullivan et al., J. Appl. Physics, 70, No. 12, (1991), 7403-7424, have explained that such a discrepancy is due to barrier height inhomogeneities, and have demonstrated that if the barrier height is assumed to follow some statistical distribution, the barrier height value extracted from C-V measurements is the arithmetic mean of the barrier height distribution (the capacitance of the Schottky contact comes from the modulation of the total space-charge as a function of bias). On the other hand, the value from I-V characterization is well below the value extracted from capacitance analysis, and is dominated by the current that flows through regions of lower barrier height. Also, the inhomogeneity of the barrier height is believed to be a primary reason for the observation of large ideality factors (n>1.1). For intimate contact and uniform MSI, the barrier height values extracted from C-V and I-V characterization are expected to be in close correlation, and ideality factors very close to unity.